Walking to school on a cold morning:
Elder offspring: I'm going to steal your warmth!
Dr. Free-Ride: Oh really?
Elder offspring sticks hands in Dr. Free-Ride's coat pockets, where Dr. Free-Ride's hands are.
Elder offspring: Brrr! Your hands are really cold!
Dr. Free-Ride: Yes, they are. Mwah ha ha!
Elder offspring: I'm still going to steal your warmth!
Dr. Free-Ride: My dear, given that in this universe heat flows from hotter objects to cooler ones, I'm pretty sure it is I who will steal your heat.
* * * * *
Toweling off after a recent swimming lesson and noting that the indoor air temperature was significantly lower than the water temperature in the heated pool:
Younger offspring: Please dry me off quickly. I'm freezing!
Dr. Free-Ride: Many are cold; few are frozen.
Younger offspring: Brr-brr-brr-brr.
Dr. Free-Ride: Oh, all right. Hey, do you know why you get cold when you get out of the pool?
Younger offspring: Because the heat-lamp isn't turned on.
Dr. Free-Ride: Sure, but you're usually cold right out of the pool even during the summer, when it's pretty warm in here.
Elder offspring: Because we're wet.
Dr. Free-Ride: Uh huh. And why does being wet make you cold? You were wet while you were in the pool swimming, and you weren't cold then.
Younger offspring: Hmm ...
Dr. Free-Ride: You remember states of matter, right?
Younger offspring: Yeah. The water in the pool is liquid.
Dr. Free-Ride: And the liquid water that clings to you when you come out of the pool -- at least, what we don't towel off of you -- is going to evaporate, which means --
Younger offspring: It's going to make storm clouds?
Dr. Free-Ride: Indoors? That would be surprising.
Elder offspring: It would be pretty cool, though.
Dr. Free-Ride: Think about how we can turn liquid water into water vapor at home in the kitchen.
Elder offspring: We heat it!
Dr. Free-Ride: That's right. So what do you think happens when the drops of water on you evaporate?
Elder offspring: It uses heat from our bodies to turn the water from a liquid to a gas!
Dr. Free-Ride: Yup. That's also why our bodies sweat. Evaporating sweat is a way to move excess heat.
Younger offspring: So evaporating water steal our warmth?
Dr. Free-Ride: That's thermodynamics for you.
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You should publish this as "Thermo - The Cliff Notes Version"!
Sprogs,
And because water is so good at stealing warmth, you can die of hypothermia (getting real cold) even when the water you're swimming in is as warm as the air; and the air can be warm enough to run around in your birthday suit in.
Janet,
I think you'll find that elder sprog has become more affectionate and more sensitive---both emotionally and in the sense of touch. In short, she's begun the great journey that changes a girl into a woman.
The story goes that once a young girl asked plaintively, "Does anybody survive puberty?"
Her mother replied, "The girl you are doesn't, the woman you become does."
Maybe I should assign this post to my freshmen who simply refuse to remember how latent heat works.
ScienceWoman,
Don't feel too bad about your freshmen, Ben Franklin was convinced hot air sank. You couldn't reason with the fellow about it.
Dr. Free-Ride: That's thermodynamics for you.
Thermodynamics is our friend! You just have to remember that it is not just a good idea, it is the law, and use it in our favor! LOL
Dave Briggs :~)
Ouch. Very ouch. Well, at least we were spared something like Im in ur pokkitz steelin ur warmth!
Elder Offspring! In this house, we obey the laws of thermodynamics!
"Dr. Free-Ride: Many are cold; few are frozen."
I admire your ability to pun on your feet this quickly. Unless, of course, you were saving this up all along, waiting for an unsuspecting victim.
F.Y.I dear readers,
Dr. Free-Ride learned to pun (defensively) at an early age at her father's knee. A conversation without a pun is like a day without sunshine, and to guard against THAT she fled the East coast for CA.